Based on the experiment on strength properties of cemented tailings backfill in cold area at low temperature,gray correlation analysis was adopted to evaluate the influence of those controlling factors on the strength properties.Results showed that under such cold condition,the strength of fill-mass increased with an increase in the cement-sand ratio,mass concentration of the slurry and curing time.It was also found that cement-sand ratio had a predominant impact on the strength of backfill,followed by the factor of curing time and mass concentration.

In-situ stress field,which is consist of self-weight stress field and tectonic stress field,is one of the most important factors in the deep underground engineering analysis.There are some defects in present commonly used three dimensional stress field simulation method,then it is not very well in maintaining ground stress field distribution rule and avoiding additional displacement.Firstly,two methods are evaluated and some Java programming is built based on the better one to create the initial stress file.And that can be done by a simple EXCEL method without programming when higher version ANSYS software is used.Then,a simple node reaction method is put forward to realize ground stress balance which means the displacement in the finite element model is zero.At last,all good methods in the process are integrated into a practical ANSYS 3-D numerical simulation method for in-situ stress field.

With the high-speed development of the national economy,the demand of mineral resources rises rapidly.In this case,the contradiction between the development of enterprises and the safety around them becomes more and more serious.In order to find out the safety characteristics and then to take scientific management countermeasures,it is very important to study deeply the relationship between the development of modern mining enterprises and the safety around them.This paper studies the basic content and characteristics of the safety around mining enterprises,explores the mutual relationships between the safety and the development of enterprises,introduce some advanced experiences of safety management for mining enterprises from foreign countries,analyzes the successful experience and failure lesson of a large underground mine in the perimeter safety management,and puts forward a safety management mode for mining enterprises which corresponds with the practical conditions of our country.